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It is crucial to address the performance deterioration of water-based drilling fluids (WDFs) in situations of excessive salinity and high temperature while extracting deep oil and gas deposits. The focus of research in the area of drilling fluid has always been on filter reducers that are temperature and salt resistant. In this study, a copolymer gel (PAND) was synthesized using acrylamide, N-isopropyl acrylamide, and 3-dimethyl (methacryloyloxyethyl) ammonium propane sulfonate through free-radical polymerization. The copolymer gel was then studied using FTIR, NMR, TGA, and element analysis. The PAND solution demonstrated temperature and salt stimulus response characteristics on rheology because of the hydrophobic association effect of temperature-sensitive monomers and the anti-polyelectrolyte action of zwitterionic monomers. Even in conditions with high temperatures (180 °C) and high salinities (30 wt% NaCl solution), the water-based drilling fluid with 1 wt% PAND displayed exceptional rheological and filtration properties. Zeta potential and scanning electron microscopy (SEM) were used to investigate the mechanism of filtration reduction. The results indicated that PAND could enhance bentonite particle colloidal stability, prevent bentonite particle aggregation, and form a compact mud cake, all of which are crucial for reducing the filtration volume of water-based drilling fluid. The PAND exhibit excellent potential for application in deep and ultra-deep drilling engineering, and this research may offer new thoughts on the use of zwitterionic polymer gel in the development of smart water-based drilling fluid.

Superwetting surfaces have the potential to address oil pollution in water, through their ability to separate the two. However, it remains a great challenge to fabricate stable and efficient separation structures using conventional manufacturing techniques. Furthermore, the materials traditionally used for oil-water separation are not stable at high temperature. Therefore, there is a need to develop stable, customizable structures to improve the performance of oil-water separation devices. In recent years, 3D printing technology has developed rapidly, and breakthroughs have been made in the fabrication of complicated ceramic structures using this technology. Here, a ceramic material with a gradient pore structure and superhydrophobic/superoleophilic properties was prepared using 3D printing for high-efficiency oil-water separation. The gradient pore structure developed here can support a flux of up to 25434 L/m2h, which is nearly 40% higher than that an analogous structure with straight pores. At 200 °C, the oil-water separation performance was maintained at 97.4%. Furthermore, samples of the material exhibited outstanding mechanical properties, and chemical stability in a variety of harsh environments. This study provides an efficient, simple, and reliable method for manufacturing oil-water separation materials using 3D printing, and may have broader implications for both fundamental research and industrial applications.

Polymer gel lost circulation control technology is a common and effective technique to control fractured lost circulation. The performance of a lost circulation control agent is the key to the success of lost circulation control techniques. In this study, rheological tests were used to study the physical and chemical properties of a shear thixotropic polymer gel system, such as anti-dilution, high temperature resistance and high salt resistance. The results showed that the shear thixotropic polymer gel system had the ability of anti-dilution, and the gel could be formed under a mixture of 3 times volume of heavy salt water and 3/7 volume white oil, and could keep the structure and morphology stable. Secondly, the gel formation time of shear thixotropic polymer gel system could be controlled and had good injection performance under the condition of 140 °C and different initiator concentrations. Meanwhile, the shear thixotropic polymer gel system had the ability of high temperature and high salt resistance, and the gel formation effect was good in salt water. When the scanning frequency was 4 Hz and the temperature was 140 °C, the storage modulus (G′) of the gel was 4700 Pa. The gel was dominated by elasticity and had excellent mechanical properties. By scanning electron microscope observation, it was found that the shear thixotropic polymer gel system had a stable three-dimensional reticular space skeleton under the condition of high salt, indicating that it had excellent ability to tolerate high salt. Therefore, the shear thixotropic polymer gel had high temperature and high salt resistance, dilution resistance and good shear responsiveness. It is believed that the results presented in this work are of importance for extending real-life applications of shear thixotropic polymer gel systems.

The failure of thickeners at high temperature results in gelled acid acidification fracturing. To solve the problem, 8 kinds of polymers were synthesized by free radical polymerization of aqueous solution using AM, AMPS, NaAMPS, MAPTAC, DTAB and NVP as raw materials. The polymer was characterized by infrared spectroscopy and viscosity-average molecular weight, and the temperature resistance, rheology, salt resistance and shear resistance of the polymer solution were compared, and the mechanism was analyzed. The results show that the viscosity of GTY−2 is 181.52 mPa·s, and the viscosity loss rate is 56.89% at 180 °C and 100 s−1, and its temperature resistance is the best. Meanwhile, the viscosity retention rate of GTY−2 is 84.58% after 160 min shear, showing the strongest shear resistance. The viscosity loss rate of GTY−1 in 20% hydrochloric acid solution is 80.88%, and its acid resistance is stronger than that of GTY−2. Moreover, due to the amphiphilicity of DTAB, the molecular hydration film becomes thicker, and the salt resistance of GTY−2 is lower than that of GTY−1. The experimental results show that GTY−1 and GTY−2 have good temperature resistance, salt resistance, acid resistance and shear resistance, and can be used as thickeners for acid fracturing with thickened acid to improve the effect of acid fracturing under high temperature conditions. Published version The authors are grateful for the National Natural Science Foundation of China (No. 51574089).

WOS: 000368956500020, This article reports a study on the microstructural and mechanical properties of the Alkali Activated Slag mortars (MS) upon exposing to the elevated temperatures up to 800 degrees C. Slag cement is activated by sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solutions with silicate modulus (Ms = SiO2/Na2O) of 1.0 and sodium (Na) dosages of 5%. MS mortars were being subjected to the ambient and high temperature curing (6 h under 60 degrees C) after undisturbed for 24 h in mold at room temperature. Ordinary Portland cement (OPC) mortar was also prepared as control. Bending and compression tests were conducted at ambient temperature and after exposure to high temperatures at 28 days. Both AAS and OPC mortars were subjected to the X-ray diffraction (XRD), scanning electron microscope (SEM), and thermogravimetric analysis (TGA) tests to find out the microstructural variation due to the exposed temperature level. Test results revealed that the high temperature resistance of the alkali activated slag mortars and Portland cement mortars are clearly different from each other's. Contrary to the expectations, brilliant mechanical and high temperature resistance might not be observed at the alkali activated slag mortars irrespective of the applied cured conditions. Additionally, applied curing regime and exposed temperature level had a significant effect on the TGA, XRD and SEM images. (C) 2015 Elsevier Ltd. All rights reserved.

Polythioether sealants are considered as new generational aeronautical sealants. First, by changing molecular structure, the feasibility of forming certain molecular weight of polythioethers was studied. Experiment show that most terminal dienes can react with dithiol generating certain molecular polythioethers. Then, analysis show that the linear polythioethers owning high degree of molecular regularity usually have rather low glass transition temperature (Tg), below -50oC, however, those polythioethers are very easily to crystalize. If they are not liquid at room temperature they can be used as raw rubber. If main chain of polythioether contains benzene ring, 5% weight loss temperatures will be improved, however, Tg will increase a lot, which cannot allow them to be used at low temperature. At last, using those polythioethers which are liquid at room temperature as raw rubber and Manganese Dioxide (MnO2) as curing agent, prepare kinds of sealants. The result shows that polythioether sealant prepared by reaction product of 1,6-Hexanedithiol and diethylene glycol divinyl ether(DGDE) has the highest tensile strength, which is 5.84MPa. After hot air aging (at 160oC and 100h), the sealant employing the polythioether synthesized by 2,2’-oxydiethanethiol and DGDE has the best thermal stability, the tensile strength only decrease 28%.

This paper presents the testing results of impact both the individual and total content of impurities in platinum and its alloys of different purity. Relative probability is presented of distribution of Al, Si, Fe, Mg, Ni, Pb, Cu, Ag, as well as their maximum content in the alloys of PtRh7, PtRh10, PtRh5Pd15 and PtRh5Pd15Ru1.5 composition. Also, the results of impact the purity degree of platinum to its high temperature resistance are given after applied thermo-mechanical processing regime. The conclusion is that, if content of impurities is higher in platinum metals and alloys, greater is the probability of their negative impact on technological and exploitation properties.

In this study, size effect on the residual properties of Engineered Cementitious Composites (ECC) was investigated on the specimens exposed to high temperatures up to 800 °C. Cylindrical specimens having different sizes were produced with a standard ECC mixture. Changes in pore structure, residual compressive strength and stress–strain curves due to high temperatures were determined after air cooling. Experimental results indicate that despite the increase of specimen size, no explosive spalling occurred in any of the specimens during the high temperature exposure. Increasing the specimen size and exposure temperature decreased the compressive strength and stiffness. Percent reduction in compressive strength and stiffness due to high temperature was similar for all specimen sizes.

In this paper the studies on reuse of ceramic sanitary ware wastes as aggregate in the concrete resistant to high temperatures are presented. Concrete specimens containing alumina cement and crushed sanitary ceramic wastes as an aggregate were heated in 1000oC. It was found that after heating, these specimens preserved their shape and cohesion, and showed no cracks and defects. In contrast, specimens of concrete with alumina cement and traditional aggregate (granite and gravel) after heating were cracked and damaged. Despite some decrease in strength after heating, specimens with sanitary ceramic wastes continued to display high compressive strength and tensile strength.